Computer and telephony networks are typically required to perform in a best effort manner and it is therefore essential to monitor network performance and network faults on these networks. For example, for Internet Protocol (“IP”) networks, network applications may require an IP service provider (“ISP”) to monitor, as a part of a service level agreement (“SLA”) between an ISP and a user/client, performance metrics such as data packet loss, round trip time and/or inter-packet jitter (i.e., inter-packet latency in arrival time) in a network. Metrics for other layers of the IP network, such as an Ethernet layer, may also need to be monitored. The service provider and users/clients therefore need a way to measure network performance metrics to ensure that the agreed level of service is maintained.